Chemical properties of different peats depending on origin and analytical method

The chemical properties of 12 different peats have been analyzed by methods from VDLUFA (German Association of Agricultural Analysis and Research Institutes) and EN (European Committee for Standardization, Technical Committee 223: Soil improvers and growing media). The analyses of pH (CaCl 2), contents of salts (H 2O), nutrients (CAT), and Na and Cl (H 2O) were carried out by VDLUFA methods, while those of pH (H 2O), EC (H 2O), nutrients (CAT), Na (CAT and H 2O) and Cl (H 2O) according to EN. Ten milled or sod white peats and two dredged frozen black peats of different degrees of decomposition were used. All of them contained high amounts of Mg, while black peats were additionally high in N, Fe and Zn. The pH-values were about the same for all peats. N- and Mn-contents depended most on peat origin. Analytical values of both CAT-methods were in the same range. Extraction with H 2O (EN) as compared to CAT (EN) resulted in considerably lower values.

Analytical model for heterogeneous crystallization kinetics of spherical glass particles

An analytical model developed to describe the crystallization kinetics of spherical glass particles has been derived in this work. A continuous phase transition from three-dimensional (3D)-like to 1D-like crystal growth has been considered and a procedure for the quantitative evaluation of the critical time for this 3D-1D transition is proposed. This model also allows straightforward determination of the density of surface nucleation sites on glass powders using differential scanning calorimetry data obtained under different thermal conditions. © 2009 The American Ceramic Society.

Monte Carlo and analytical calculation of lateral deflection of proton beams in homogeneous targets

Proton radiation therapy is a precise form of radiation therapy, but the avoidance of damage to critical normal tissues and the prevention of geographical tumor misses require accurate knowledge of the dose delivered to the patient and the verification of his position demand a precise imaging technique. In proton therapy facilities, the X-ray Computed Tomography (xCT) is the preferred technique for the planning treatment of patients. This situation has been changing nowadays with the development of proton accelerators for health care and the increase in the number of treated patients. In fact, protons could be more efficient than xCT for this task. One essential difficulty in pCT image reconstruction systems came from the scattering of the protons inside the target due to the numerous small-angle deflections by nuclear Coulomb fields. The purpose of this study is the comparison of an analytical formulation for the determination of beam lateral deflection, based on Molière's theory and Rutherford scattering with Monte Carlo calculations by SRIM 2008 and MCNPX codes. © 2010 American Institute of Physics.

Recent applications of analytical techniques for quantitative pharmaceutical analysis: A review

The intension of this paper was to review and discuss some of the current quantitative analytical procedures which are used for quality control of pharmaceutical products. The selected papers were organized according to the analytical technique employed. Several techniques like ultraviolet/visible spectrophotometry, fluorimetry, titrimetry, electroanalytical techniques, chromatographic methods (thin-layer chromatography, gas chromatography and high-performance liquid chromatography), capillary electrophoresis and vibrational spectroscopies are the main techniques that have been used for the quantitative analysis of pharmaceutical compounds. In conclusion, although simple techniques such as UV/VIS spectrophotometry and TLC are still extensively employed, HPLC is the most popular instrumental technique used for the analysis of pharmaceuticals. Besides, a review of recent works in the area of pharmaceutical analysis showed a trend in the application of techniques increasingly rapid such as ultra performance liquid chromatography and the use of sensitive and specific detectors as mass spectrometers.

Savings, investment and growth in the global age: analytical and policy issues

Includes bibliography

Representation of transmission lines in modal domain using analytical transformation matrices

The phases of a transmission line are tightly coupled due to mutual impedances and admittances of the line. One way to accomplish the calculations of currents and voltages in multi-phase lines consists in representing them in modal domain, where its n coupled phases are represented by their n propagation modes. The separation line in their modes of propagation is through the use of a modal transformation matrix whose columns are eigenvectors associated with the parameters of the line. Usually, this matrix is achieved through numerical methods which does not allow the achievement of an analytical model for line developed directly in the phases domain. This work will show the modal transformation matrix of a hypothetical two-phase obtained with numerical and analytical procedures. It will be shown currents and voltage s at terminals of the line taking into account the use of modal transformation matrices obtained by using numerical and analytical procedures. © 2011 IEEE.

The institutionality of gender in the State: new analytical perspectives

Includes bibliography

Modelling thermodynamic properties of banana waste by analytical derivation of desorption isotherms

Banana is an agricultural product of great economic importance for various developing countries. The relationship between moisture content and water activity provides useful information for the processing and storage of banana waste. The water activity and moisture content of three banana (Mussa spp. Haploid AAB cv. Nanica) waste items were analyzed to determine the desorption isotherms at six different temperatures (20, 30, 40, 50, 60 and 70°C). The desorption isotherms of the peel, pedicel and pulp of overripe bananas were determined in wide ranges of moisture content (0.001-6.360 kg kg-1 d.b.) and water activity (0.02-0.907). The theoretical GAB model was used for modelling the desorption isotherms. An analytical solution of the Clausius-Clapeyron equation was proposed to compute the isosteric heat of sorption, the differential entropy and Gibbs' free energy by way of the GAB model when the effect of temperature on the hygroscopic equilibrium was considered. © 2012 de Gruyter. All rights reserved.

Spin stabilized satellite's attitude analytical prediction

An analytical approach for spin stabilized attitude propagation is presented, considering the coupled effect of the aerodynamic torque and the gravity gradient torque. A spherical coordination system fixed in the satellite is used to locate the satellite spin axis in relation to the terrestrial equatorial system. The spin axis direction is specified by its right ascension and the declination angles and the equation of motion are described by these two angles and the magnitude of the spin velocity. An analytical averaging method is applied to obtain the mean torques over an orbital period. To compute the average components of both aerodynamic torque and the gravity gradient torque in the satellite body frame reference system, an average time in the fast varying orbit element, the mean anomaly, is utilized. Afterwards, the inclusion of such torques on the rotational motion differential equations of spin stabilized satellites yields conditions to derive an analytical solution. The pointing deviation evolution, that is, the deviation between the actual spin axis and the computed spin axis, is also availed. In order to validate the analytical approach, the theory developed has been applied for spin stabilized Brazilian satellite SCD1, which are quite appropriated for verification and comparison of the data generated and processed by the Satellite Control Center of the Brazil National Research Institute (INPE). Numerical simulations performed with data of Brazilian Satellite SCD1 show the period that the analytical solution can be used to the attitude propagation, within the dispersion range of the attitude determination system performance of Satellite Control Center of the Brazilian Research Institute.

Analytical direct planetary perturbations on the orbital motion of satellites

An analytical expansion of the disturbing function arising from direct planetary perturbations on the motion of satellites is derived. As a Fourier series, it allows the investigation of the secular effects of these direct perturbations, as well as of every argument present in the perturbation. In particular, we construct an analytical model describing the evection resonance between the longitude of pericenter of the satellite orbit and the longitude of a planet, and study briefly its dynamic. The expansion developed in this paper is valid in the case of planar and circular planetary orbits, but not limited in eccentricity or inclination of the satellite orbit. © 2012 Springer Science+Business Media Dordrecht.

Development of an analytical method for the quantification of pfaffic acid in Brazilian ginseng (Hebanthe eriantha)

Hebanthe eriantha (Poir.) Pedersen (Amaranthaceae), which is known as Brazilian ginseng is widely used in folk medicine as an aphrodisiac and antidiabetic tonic. The anti-tumor activity, attributed to the pfaffic acid present in roots of H. eriantha, is responsible for the great interest in the commercialization of this species. In Brazil, the species H. eriantha is mainly used in commercial preparations, although other plants of the genus Pfaffia and Hebanthe have been marketed as Pfaffia paniculata or Brazilian ginseng. The pfaffic acid present in the roots is mainly conjugated with sugars (pfaffosides) and can be used as an active marker of H. eriantha, which helps to differentiate this species from others marketed as Brazilian ginseng. The main objective of this study was to develop and validate a liquid chromatographic method to quantify pfaffic acid in the roots of H. eriantha. The extraction and hydrolysis conditions were optimized using an univariate and experimental design, respectively, and the quantification of pfaffic acid by high performance liquid chromatography with diode-array detection (HPLC-DAD) was validated. This method was used to evaluate the pfaffic acid content in 30 different genotypes of the species from a germplasm collection. The content of pfaffic acid ranged from 0.97 to 4.29% (w/w) on a dry weight basis. © 2013 Elsevier B.V.

Validation of an alternative analytical method for the quantification of antioxidant activity in plant extracts

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Orbifloxacin: A Review of Properties, Its Antibacterial Activities, Pharmacokinetic/Pharmacodynamic Characteristics, Therapeutic Use, and Analytical Methods

Orbifloxacin is a third generation of fluoroquinolone that exhibits increased antibacterial activity against the Enterobacteriaceae, gram-negative and gram-positive bacteria, anaerobes, and mycobacteria. This drug was synthesized in 1987 and developed as a veterinary chemotherapeutic to use for livestock and domestic pets. Orbifloxacin is labeled for the treatment of skin, soft tissue, and urinary tract infections in dogs, and skin and soft tissue infections in cats, but in some countries, orbifloxacin has been given for the treatment of gastrointestinal and respiratory infections in cattle and swine and other animals. The in vitro activity and clinical efficacy of orbifloxacin against naturally occurring bacterial infections of the skin, ear, soft tissue, udder, and gastrointestinal and respiratory systems in different animals have been evaluated and good responses have been found. The minimum inhibitory concentration of orbifloxacin has been determined in various different pathogens and the results found in the literature are shown in this work. The pharmacokinetics of orbifloxacin has been evaluated by different routes of administration in goats, horses, pigs, rabbits, dogs, cats, camels, cattle, sheep, and fish. Orbifloxacin exhibits excellent pharmacokinetic parameters that suggest that this drug may have good clinical effects on various bacterial infections in these species. All methods described in the scientific literature for determination of orbifloxacin in different matrices were collected and discussed. © 2013 Copyright Taylor and Francis Group, LLC.